Bruce Palmer

Take the train out (see some country) and drive it back.

We've spoken

Lotta that going around....... nyuck nyuck

Original post was 2/23/09..... Glad to see I'm not the only one who jumps on and answers a moldy oldie.....

Needle nosed Vice Grips in that un threaded section in the middle works fine.

It would have been easier to screw the longer studs out and put them in the other manifold than it was to swap manifold. A small pair of vice grips should start'em and finger 'em out from there. I know, too late now. Hope you install seals uo alright and you have no leaks. Oh, and I'm one of those who surmise the flat top manifold "might" flow a little better than the early ones. That's a totally undocumented "nothing behind it" surmisings based on just looking in the intakes side by side......

Is this a great forum or what? Final analysis. Our Euro balance tube has provision for PCV and brake booster and one cartb has a tap for vacuum to the distributor. All the rest of that is just supefluous..... Flat top manifold, early balance tube, long studs, thick insulators, round tops, heatshield of your choice and you should be good to go. Oh, and the early air cleaner. Been done thousands of times. I am still surprised about how many cars are just now getting around to making the swap as NISSAN did the swap for new owners when the flat top cars first hit the streets, to keep the new owners from mutinying.

Dangit!! There was a drop dead killer thread on here within the last week showing step by step photos with discussion on this very subject. Hateit when that happens. Bueller? Anyone? Why isn't this ibn the carb section?

Just guessing here but the turbo pump should be about more volume as it had to not only supply the engine oiling galleys and bearings but the turbo system outside the block. I ran the high volume pump on my LZ four and went back to the stock volume pump because the high volume pump was piling up too much oil on top of the head essentilly drowning the valve seals. Pressure should be controlled to a fair extent by bearing clearances. The more worn the engine the lower the pressure over the span. That's why people keep wanting to stuff thicker oil into old motors to slow down the flow with the idea that that is going to increase the pressure..... Just sayin'

Remove all the fittings and fill the holes with little freeze pugs with a little goop to hold'em in place. Chicks'll look in there and see something silver and go "OOOoooo". You can clean up all the "water around the block" stuff at the same time.

This is one of those questions where after asking 15 people you'll get 17 "opinions". Only you can answer the questions of the what ifs. I'd say build both, load both, drive it for a loooong time. Fresh is the only sure way of knowing you'll have "more". "OPINION #1".

And don't lose sight of the fact that keeping then carbs on the bigger motor is a bolt on. No harness issues, no fuel pump issues, etc. Keeps the cobble factor down to a minimum.....

So how fortuitous is that? You come on here asking this and 2 hours later a pictoral is posted covering what your answers here were spelling out. SUs and the Hitachi variant (re Datsuns) once returned to square one status, are the easiest carbs in the world to keep up with and the flat top conversion is a near bolt on conversion.

I'd guess these are aftermarket needles turned out by someone who maybe doesnt have total product control. Two things. Make sure the set screw is backed out enough to clear and run a q-tip up in the hole to see it it snags on a burr or anything up in the piston. If the hole is clear then buff the head of the needle with some 320 grit paper until you get clearance. You force it you, bend it....... Both of the stock needles tended to run fat at idle and lean up top. That's comparing the N54 smogger needle to the SM needle which was the first step up in carb perfoormance way back in the mid 70s when they first started on performance mods on the L motor. The SM leans things down at idle and fattens things up up top. All the nozzles are the same regardless of whether they are three or four screw carbs. .100" orifice

You learn something every day..... or should. Just asked Steve the owner of Zed Therapy about the hole thing and he pawed through his pile and said almost all his backing plate have ONE hole, Every so often he'll see one with two but the second hole has been drilled. Roadsters and SSS setups all have both holes in the backing plates. I pride myself on having very limited knowledge on this subject because for several years getting us out of the aircleaner business was a primary goal of mine.

Does the backing plate only have one hole in it like the gasket? I'd stay with the stock aircleaner. Able to pull cooler air in from upfront, has good stacks built it, and feeds both carbs from a common air source. The individual air cleaners supply each carb from a different source (potential unbalance siuation) and pulls hot air right off the exhaust manifold. Also you have to make provisions for float bowl venting and come up with seperate air horns.

These MGB may be an oddity at 1 3/4" and are HS6 an equivalent to the 46mm Hitachis. The Burlin book I have shows the 70s MGBs ran HS4s or 38mm carbs on the 1800. Right thru that series the SU numbers I see are all right in that range. I just don't see AUD 425.....

I have been unable to find that model number in the SU book. Why do you ask? FWIW F & R stand for Front and Rear. Sorry I can't be of more help.

A couple of thoughts relating to that picture that bear study. Tube headers, like those, often interfere with the installation of a heat shield, which then requires wrapping the tubing headers with the heat wrap, which in turn can result in premature burn out of the headers. Pretty cool program just to be able to say "my car has headers" and all the problems that go with. Just saying.......

See Jim, I told you the info would be rattling around in the hallowed halls of Classic Z cars dot com. We will proceed accordingly, diggin' and a scroungin', diggin' and a scroungin'.

So you suppose at Odark 30 on my way to the pool I'm going to spell check?

The only dumb question would be the one you already know the answer to. The thread is just another in a looooong list of goodies where the question was well stated and the quality of the answers were remarkable. Olzed, looks like you have a new neighbor in Malasia.

And if you think your English is bad, well try my Malasian. Welcome to the forum. It is a pretty good bunch of guys with good knowledge for the most part and a willingness to share..... Oh, and you need carbs...... nyuck nyuck We do have members in Australia and I believe New Zealand. Would they be good sources for you? Anyway, keep posting and let's see who surfaces.

Another set of qualifiers to consider are the other pieces of the drive train. That short stroke L-20 Z with the 38mm Hitachis is from what I understand a pretty neat set up. But from a driveabilty setup because of the short stroke engine, isn't the tranny gearing and the rear end gearing entirely different than what you would start with in the 240 etc? So what I'm driveing at is in order to be happy with than buzzy SR and expect it to pull a Z comfortably, I'm thinking you'll be swapping out more than just the engine and harnesses. Don't know but I'd guess the SR won't bolt up to the Z tranny so you would more than likely be needing to fab an new tranny mount, make a new driveline, match up an SR Speedo drive to the Z speedo. Of course you'll be needing to build a new exhaust system too, oh and motor mounts and adapting a cooling system to the SR. If it were me and a turbo set up was the flavor of the day, I'd put better money into finding a good running 280 ZX Turbo and making it the best you can make it. At least that setup was engineered fr4om the ground up as a unit. I'd bet if you asked any engineer at NISSAN about this swap idea they'd say to forget it.

There should be some complete EFI "take outs" around for sale as a number of 280 owners have gone to the early round top Hitachis to get away from degrading EFI systems. I know Steve Epperly has done several here at ZTherapy but I don't know what he does with the EFI "left behinds". If you'd like I can ask him. Oh and 2.8 motors will work fine w/46mm Hitachis if that's what you are fearing..